DOC AIRBUS | AMM A320FTemporary Modification of the JH1 and JH2 Routing for Aircraft Dispatch Requirements [CFMB]
TASK 74-31-00-040-005-A
Temporary Modification of the JH1 and JH2 Routing for Aircraft Dispatch Requirements
MMEL 74-31-01A
IGNITION SYSTEM A (FAA ONLY)
left ignition lead on aircraft battery bus. MMEL743101
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 74-31-00-861-052-A ** ON A/C NOT FOR ALL Subtask 74-31-00-941-054-A ** ON A/C NOT FOR ALL
Subtask 74-31-00-020-051-A ** ON A/C NOT FOR ALL
Subtask 74-31-00-440-054-A ** ON A/C NOT FOR ALL Subtask 74-31-00-410-052-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 03:07:54 UTC
Temporary Modification of the JH1 and JH2 Routing for Aircraft Dispatch Requirements
WARNING:
BEFORE YOU START WORK ON THE IGNITION SYSTEM, MAKE SURE THAT THE IGNITION EXCITERS ARE DE-ENERGIZED FOR A MINIMUM OF FIVE MINUTES. ALSO DO NOT TOUCH THE ELECTRICAL CONTACTS.
THE IGNITION SYSTEM VOLTAGE IS VERY HIGH, AND THE IGNITION EXCITERS CAN HAVE AN ELECTRICAL CHARGE EVEN WHEN NOT ENERGIZED. IF YOU DO NOT OBEY THESE PRECAUTIONS, INJURY CAN OCCUR.
CAUTION:
BE CAREFUL WITH THE IGNITION LEAD TO PREVENT DAMAGE TO THE CONDUIT AND THE INTERNAL WIRES.
1. Reason for the JobMMEL 74-31-01A
IGNITION SYSTEM A (FAA ONLY)
left ignition lead on aircraft battery bus. MMEL743101
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE |
| No specific | AR | PLIERS - NOSE, SOFT, LONG |
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| No specific | AR | WARNING NOTICE(S) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| FOR [1000EM1] (ENGINE-1) | |
| 437AL, 438AR | |
| FOR [1000EM2] (ENGINE-2) | |
| 447AL, 448AR | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 24-41-00-861-002-A | Energize the Aircraft Electrical Circuits from the External Power |
| TASK 24-41-00-861-002-A-01 | Energize the Aircraft Electrical Circuits from the APU |
| TASK 24-41-00-861-002-A-02 | Energize the Aircraft Electrical Circuits from Engine 1(2) |
| TASK 24-41-00-862-002-A | De-energize the Aircraft Electrical Circuits Supplied from the External Power |
| TASK 24-41-00-862-002-A-01 | De-energize the Aircraft Electrical Circuits Supplied from the APU |
| TASK 24-41-00-862-002-A-02 | De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2) |
| TASK 71-13-00-010-040-B | Opening of the Fan Cowl Doors |
| TASK 71-13-00-410-040-B | Closing of the Fan Cowl Doors |
| TASK 74-00-00-710-043-A | Operational Test of the Ignition System |
| TASK 74-00-00-710-043-A-01 | Operational Test of the Ignition System without CFDS |
| TASK 78-30-00-081-041-B | Make the Thrust Reverser Serviceable after Maintenance |
| TASK 78-30-00-481-041-B | Make the Thrust Reverser Unserviceable for Maintenance |
Temporary Modification of the JH1 and JH2 Harnesses Routing and ConnectionSubtask 74-31-00-861-052-A ** ON A/C NOT FOR ALL Subtask 74-31-00-941-054-A ** ON A/C NOT FOR ALL
B. Safety Precautions
(1) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(2) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
Subtask 74-31-00-865-059-A ** ON A/C NOT FOR ALL (1) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(2) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).
C. Open, safety and tag this(these) circuit breaker(s):
Subtask 74-31-00-010-052-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | ENGINE/1 AND 2/IGN/SYS A | 1JH | A03 |
| FOR FIN: 1000EM1 (ENGINE1) | |||
| 121VU | ENGINE/IGN/ENG1/SYS B | 3JH1 | P41 |
| 121VU | ENGINE/IGN/ENG1/SYS A BAT | 2JH1 | P39 |
| FOR FIN: 1000EM2 (ENGINE2) | |||
| 121VU | ENGINE/IGN/ENG2/SYS B | 3JH2 | P42 |
| 121VU | ENGINE/IGN/ENG2/SYS A BAT | 2JH2 | P40 |
D. Get Access
(1) Open the fan cowl doors: (Ref. AMM TASK 71-13-00-010-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Put an ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE in position.
Subtask 74-31-00-040-051-A ** ON A/C NOT FOR ALL 4. Procedure(1) Open the fan cowl doors: (Ref. AMM TASK 71-13-00-010-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Put an ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE in position.
Subtask 74-31-00-020-051-A ** ON A/C NOT FOR ALL
A. Put the 4000JH1 and 4000JH2 wiring harness routings and connections to the modified configuration as follows:
(1) Disconnect the 4000JH1 harness connector from the upper ignition exciter-A.
(2) Disconnect the 4000JH2 harness connector from the lower ignition exciter-B.
(3) Make sure that the electrical connections are clean and in the correct condition.
(4) Route the 4000JH2 as follows:
(a) Connect the 4000JH2 harness connector to the upper ignition exciter-A by hand. Use PLIERS - NOSE, SOFT, LONG only if necessary.
(5) Route the 4000JH1 harness as follows:
(a) Connect the 4000JH1 harness connector to the lower ignition exciter-B by hand. Use PLIERS - NOSE, SOFT, LONG only if necessary.
(6) Make sure that no contact of the harnesses with the ignition exciter can occur.
Subtask 74-31-00-865-060-A ** ON A/C NOT FOR ALL (1) Disconnect the 4000JH1 harness connector from the upper ignition exciter-A.
(2) Disconnect the 4000JH2 harness connector from the lower ignition exciter-B.
(3) Make sure that the electrical connections are clean and in the correct condition.
(4) Route the 4000JH2 as follows:
(a) Connect the 4000JH2 harness connector to the upper ignition exciter-A by hand. Use PLIERS - NOSE, SOFT, LONG only if necessary.
(5) Route the 4000JH1 harness as follows:
(a) Connect the 4000JH1 harness connector to the lower ignition exciter-B by hand. Use PLIERS - NOSE, SOFT, LONG only if necessary.
(6) Make sure that no contact of the harnesses with the ignition exciter can occur.
B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 74-31-00-710-054-A ** ON A/C NOT FOR ALL 5. Close-up| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | ENGINE/1 AND 2/IGN/SYS A | 1JH | A03 |
| FOR FIN: 1000EM1 (ENGINE1) | |||
| 121VU | ENGINE/IGN/ENG1/SYS B | 3JH1 | P41 |
| 121VU | ENGINE/IGN/ENG1/SYS A BAT | 2JH1 | P39 |
| FOR FIN: 1000EM2 (ENGINE2) | |||
| 121VU | ENGINE/IGN/ENG2/SYS B | 3JH2 | P42 |
| 121VU | ENGINE/IGN/ENG2/SYS A BAT | 2JH2 | P40 |
Subtask 74-31-00-440-054-A ** ON A/C NOT FOR ALL Subtask 74-31-00-410-052-A ** ON A/C NOT FOR ALL
B. Close Access
(1) Close the fan cowl doors: (Ref. AMM TASK 71-13-00-410-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
(4) Make an entry in the logbook.
(5) Put a WARNING NOTICE(S) to tell persons that the ignition leads are routed to opposite ignition exciters to allow dispatch with the left ignition lead on aircraft battery bus.
Subtask 74-31-00-862-052-A ** ON A/C NOT FOR ALL (1) Close the fan cowl doors: (Ref. AMM TASK 71-13-00-410-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
(4) Make an entry in the logbook.
(5) Put a WARNING NOTICE(S) to tell persons that the ignition leads are routed to opposite ignition exciters to allow dispatch with the left ignition lead on aircraft battery bus.